Recently, there are many vehicles, each of which mounts an electric power steering system (i.e., EPS) for assisting a driver to operate a steering wheel with using a motor. In this case, an electric control device for controlling the motor is mounted on the vehicle.
The electric control device is mounted, for example, near a column shaft. In this case, liquid such as dew (e.g., condensation water) or wash fluid for a compartment may drop on the electric control device, so that the liquid penetrates into the electric control device via a clearance between a cover element and an accommodation element. Thus, a system of the device may shut down. In order to protect the device from wetting with water, it is proposed that a sealing member is filled between a casing (as the accommodation element) and a cover (as the cover element) so that the device is sealed (in, for example, JP-A-2007-273807 and corresponding US 2007/0230137).
Alternatively, the electric control device may be packed with a water-resistant sheet.
However, each of a method for filling with the sealing member and a method for packing with the water-resistant sheet provides high manufacturing cost, and further, low workability. Further, it is difficult to obtain a complete water protection effect even when the above water protection method is executed.